Facing sanctions, Iran has once again threatened to choke off the Strait of Hormuz, the only way into and out of the Gulf for oil tankers.

What to do when international talks begin falling apart? Send a fleet of unmanned submersibles in preparation for a waterway showdown. As US talks with Iran over their nuclear program began to sour and the possibility of sanctions against the country rose, Iran responded by threatening to cut off the Strait of Hormuz, a narrow waterway and the only way into and out of the petroleum-rich Persian Gulf. The US responded in turn, the LA Times reports, by sending dozens of SeaFox unmanned submersibles to the region to seek out and destroy mines in the strait.

Each SeaFox is outfitted with an underwater television camera, homing sonar, an explosive charge, and is controlled through an optic fiber tether. None of the submersibles, however, return from a successful mission as they end, not only with the destruction of the mine, but the craft itself, each costing about $100,000. The SeaFox can sniff out both submerged and surface mines.

The SeaFox is the unmanned underwater vehicle (UUV) made by the German company Atlas Elektronik. It measures about 4 feet long and weighs just under 100 pounds. Their small size enables them to be deployed from helicopters, small rubber boats, or dropped from minesweeping ships. Its maximum operational depth is about 300 meters and it can run for around 100 minutes without having to return and recharge.